Electronic yarn cleaner

ABSTRACT

A yarn cleaner capable of generating a signal for instigating the cutting of a travelling yarn in response to the thickness thereof measured in relation to the length thereof, only when the value of this signal exceeds a predetermined value. For determining as to whether the value of the instigating signal exceeds the predetermined value, a plurality of counters is provided from which the instigating signal can be generated in response to the achievement of a specific condition.

United States Patent 1 Aihara etal.

[4 1 July 31,1973

1 1 ELECTRONIC YARN CLEANER [75] Inventors: Wataru Aihara; Takashi Kawamoto,

both of Kyoto, Japan [73] Assignee: Shimadzo Seisakusho Ltd., Kyoto City, Japan [22] Filed: Oct. 15, 1971 [21] Appl. No.: 189,542

[30] Foreign Application Priority Data Oct. 20, 1970 Japan 45/92687 [52] US. Cl .L 28/64, 73/160, 324/61, 328/271 [51] Int. Cl. D02j 1/14 [58] Field of Search 28/64; 324/61; 328/271; 73/160 [56] References Cited UNITED STATES PATENTS 3,188,564 6/1965 Felix 324/61 3,477,021 11/1969 Dosch et'al 28/64 X 3,557,615 1/1971 Seymour et al... 3,631,354 12/1971 Werfeli Primary Examiner-Louis K. Rimrodt Attorney-E. F. Wenderoth, V. M. Creedon et al.

[5 7] ABSTRACT A yarn cleaner capable of generating a signal for instigating the cutting of a travelling yarn in response to the thickness thereof measured in relation to the length thereof, only when the value of this signal exceeds a predetermined value. For determining as to whether the value of the instigating signal exceeds the predetermined value, a plurality of counters is provided from which the instigating signal can be generated in response to the achievement of a specific condition.

7 Claims, 10 Drawing Figures PAIENTEDJULIBHSYS 3,748,707

SHE 1 0F 7 Fig.

WATARU AJHARA and 'IAKASHI KAWAMOTO,

INVENTOR s wmwjm ATTORNEY S PATENTEDJULBI I973 3,748.70?

SHEET u or 7 Fig. 6

WATARU AIHARA AND TAKASHI KAWAMOTO INVENTORS ATTORNEY S PATENTED JULB] I975 SHEET 7 OF 7 Fig. [0

WATARU AIHARA and TAKASIII KAWAMOTO,

INVENTORs BY wMW PM ATTORNEY s 1 ELECTRONIC YARN CLEANER The present invention relates to an apparatus for removing coarse portions of a travelling yarn and, more particularly, to an electronic yarn cleaner by whicha n electrical signal representative of the presence of the coarse portion in the travelling yarn departing from a tolerable range of length specified with respect to the measured thickness can be generated for instigating the cutting of the travelling yarn. I

Particularly, the present invention is useful in the textile industry wherein a winding machine for winding yarn from a slubbing bobbin onto a bobbin thereby to form a cross-wound cone is utilized. However, the present invention is, in its nature, utilizable in any field of industry where winding of yarn, single fiber, thin metal wire or the like is effected.

Heretofore, individual measuring devices for measuring the thickness of a travelling yarn and for measuring the length of yarn passed therethrough have been well known. However, it is preferable to combine these measuring devices so that signals from these measuring devices can be processed to give an output signal representative of the thickness and length of coarse yarn of the travelling yarn. It is true that, unless otherwise the length of coarse yarn of the travelling yarn departs from a tolerable range to an abnormally excessive extent, the quality of such yarn is not considered as badly affected even if the measured thickness of the coarse yarn departs from a tolerable range of thickness. By way of example, if it is assumed that do denotes the standard thickness, d denotes the thickness from the standard thickness, that is, the measured thickness, and

l L denotes the acceptable length of coarse yarn, then,

when the difference between the standard thickness do and the measured thickness d is of a relatively smaller value the acceptable length L may be preferably enlarged and, on the other hand, when said difference is of a relatively larger value, the acceptable length L may be preferably reduced. However, to the travelling yarn is subjected to cutting irrespective of the acceptable length L if and only if the difference between the standard thickness do and the measured thickness d exceeds a predetermined value.

The above mentioned suggestion can be achieved, if the electronic yarn cleaner is designed such that means is provided for substantially measuring the product of the difference (d do) multiplied by the length L so that a signal for instigating the cutting of the travelling yarn can be generated when the value of said product exceeds a predetermined value Vo which is substantially a function of said difference (11 do) and length L.

In a conventional electronic yarn cleaner of similar character, the measured thickness of the travelling yarn is integrated by the time while the speed of the travelling yarn is assumed to be constant, so that the product V of the difference (d do) multiplied by the length L can be obtained. However, according to this method, if the yarn speed varys, the time required for the yarn of a specific length to pass will correspondingly vary as compared with the time before the yarn speed has varied. Accordingly, this results in variation in the value V. In order to eliminate this disadvantage, the time constant of an integrating circuit provided in the conventional yarn cleaner should be changed when the speed of the travelling yarn is to be changed. This requires a time-consuming effort in the event that a plurality of threads of yarn running parallel to each other are subjected to the measurement.

Accordingly, the present invention has for its essential object to provide an apparatus for removing coarse portions of a travelling yarn wherein the signal for instigating the cutting of the yarn by which the cutting device is actuated can be generated as representative of the presence of coarse yarn as well as the length-of such coarse yarn without being affected by the speed of the travelling yarn.

Another object of the present invention is to provide an apparatus for removing coarse portions of a travelling yarn wherein means is provided to enable the instigating signal to be generated even when yarn having two or more coarse portions adjacently located is passed through the yarn cleaner.

A further object of the present invention is to provide an apparatus for removing coarse portions of a travelling yarn which can be manufactured at low cost with an improved reliability.

According to the present invention, an essential feature is that generation of the signal for instigating the cutting of the travelling yarn is not affected by the speed of said travelling yarn. Accordingly even if variations in the speed of the travelling yarn take place during the starting and runout periods of the yarn cleaner or those of a winding machine, the yarn cleamer of the present invention operates in the substantially same manner as it does when the speed of the travelling yarn is constant.

Furthermore, according to one of the preferred embodiments herein disclosed, the signal representative of the logical product of the measured thickness and the measured length obtained during the measurement of such thickness is classified into a plurality of ranks by corresponding discriminators, with which one of the counters associated with one of the ranks to which the measured thickness belongs can be operated to count the number of the signals representative of the logical product. The instigating signal for operating the cutting device can be generated only when the counted number of the signals representative of the logical product attains or coincides with a predetermined value set in said corresponding counter.

The present invention will be hereinafter fully described by way of example in conjunction with preferred embodiments thereof shown in the accompanying drawings, in which;

FIG. 1 is a schematic diagram showing various types of coarse or defective yarn which can be measured by an electronic yarn cleaner of the'present invention,

FIG. 2 is a schematic block diagram of one preferred embodiment of the yarn cleaner according to the present invention,

FIG. 3 is a schematic block diagram of another preferred embodiment of the present invention,

FIG. 4 is a schematic diagram showing a program on which the operation of the yarn cleaner of FIG. 3 is based, this program being shown only for the purpose of illustration,

FIG. 5 is a block diagram of a modification of the yarn cleaner of FIG. 3 wherein each counter shown in FIG. 3 is replaced by an adder,

FIG. 6 is a schematic block diagram of a further embodiment of the present invention,

FIG. 7 is a logical diagram of a still further embodiment of the present invention,

FIG. 8 and FIG. 9 are diagrams of modifications of the embodiments shown in FIG. 2 and FIG. 6, respectively, and

FIG. 10 is a schematic diagram showing the arrangement of a winding machine to which the present invention is applicable for illustrating various positions at which detection of the yarn length and yarn thickness is possible.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the several views of the accompanying drawings. In addition, it is to be noted that, after the coarse yarn of the travelling yarn has been removed, the winding operation is usually to facilitate the formation of a knot by means of a knotting device. However, for the purpose of brevity, the description of this knotting procedure is herein omitted and it may be executed in a known manner. And detailed formation of each component of the present invention hereinafter described is also omitted. These components can be suitable conventional ones as such as a discriminater circuit which comprises a filter.

Referring first to FIG. 2, a fundamental form of electronic yarn cleaner embodying the present invention is shown in block diagram. A yarn 10 as shown is adapted to travel from a slubbing bobbin 11 to a cross-wound cone 12 while being guided by a split guiding drum 13. The latter is usually driven by a suitable drive motor (not shown) and, since the peripheral surface of said drum 13 is resiliently engaged with that of the crosswound cone 12, rotates the latter in the opposite direction with respect thereto so that the yarn 10 can be wound onto the cone l2.

Disposed adjacent to a substantially intermediate portion of the yarn 10 passing from the slubbing bobbin 11 onto the cross-wound cone 12 is a measuring device 14. This measuring device 14 comprises a yarn length measuring unit 15 for measuring the length of yarn passed therethrough and generating pulsating signals representative of the length of yarn passed therethrough and a yarn thickness measuring unit 16 for measuring the thickness of the travelling yarn 10 and generating a signal representative of the thickness of the yarn passed therethrough.

The yarn length measuring unit 15 includes a source 15a of light, a photosensitive element 15b such as a photoelectric cell and a freely rotatable chopper roller 15c of sufficient thickness having along its peripheral surface a groove in which the travelling yarn 10 is engaged without any slip occurring between said yarn 10 and said groove of said chopper roller 15c, said roller 150 being also having a plurality of equally spaced holes 15d all extending across the thickness of said roller 150. The arrangement of these elements of the yarn length measuring unit 15 is such that any one of the holes 15d of the chopper roller 15c can be brought into alignment with a beam of light transmitted from the light source 150 to the photosensitive element 15b as said roller 15c is rotated in contact with the travelling yarn 10. In other words, as the roller 15c is rotated, the beam of light transmitted from the light source 15a can be alternately intercepted or passed through the holes 15d of the roller 15c in response to the absence or presence of each of the holes 15d in the path of said light beam, this behavior of said light beam being detected by the photosensitive element 15b from which electric pulses can be subsequently generated. It is to be noted that generation of the number of pulses'from the photosensitive element which is substantially equal to the number ofthe holes 15d indicates the passage of yarn 10 of a length substantially equal to the circumference of the chopper roller 15c. Hence, each interval between one pulse to another indicates the passageof yarn of a length substantially equal to the quotient of the circumference of the roller 15c divided by the whole number of pulses generated from the photosensitive element 15!) during one rotation of the roller 150.

The yarn thichness measuring unit 16 includes a source 16a of light and a photosensitive element 16b which may be the same as the photosensitive element 15b and disposed so as to receive a beam of light from the light source 16a transmitted across the yarn 10. The thickness of the yarn 10 passing through said measuring unit 16 can be determined by the intensity of light detected by the photosensitive element 16b. lt is to be noted that it is not necessary to employ the two sources of light. A common source of light can be used in connection with the two photosensitive elements 15b and 16b.

The pulses representative of the yarn length which are generated from the photosensitive element 15b are fed to a waveform shaping circuit 17 through an amplifier 18. This shaping circuit 17 is provided for shaping the pulses from the photosensitive element 15b which are usually distorted due to some reason, for example, variation in the intensity of light transmitted by the light source 15a or received by the photosensitiveelement 15b. If the pulses from the photosensitive element 15b are not distorted, this shaping circuit 17 may be omitted. The shaped pulses from the shaping circuit 17 are in turn fed to an AND gating element 19.

The electric signal representative of the yarn thickness which is generated from the photosensitive element 16b is fed to a discriminator circuit 20 through an amplifier 21. The discriminator circuit 20 is adapted to compare the signal representative of the yarn thickness with a reference signal applied thereto from a reference signal generating circuit 22 and, only when the level of the signal representative of the yarn thickness is found to be higher or lower than the level of the reference signal, does'said discriminator circuit 20 generate an error signal and supply it to the AND gating element 19. The level of the signal representative of the yarn thickness varys in response to the thickness of the travelling yarn 10 in such a way that, when a coarse or defective portion of of the travelling yarn 10 such as shown in FIG. 1 is passed across the path of the light beam transmitted from the light source 16a onto the photosensitive element 16b, the level of the signal from said element 16b is either increased or decreased in response to the thickness of said coarse portion of the travelling "yam 10, whereas the level of the reference signal should be preselected so as to correspond to a yarn having a standard thickness of the value within a tolerable or desired range which is determined depending upon the kind of yarn used and/or the commercially acceptable quality given to a specific yarn.

The gating element 19 can be triggered on by the logical product of the shaped pulses representative of the yarn length and the error signal from the discriminator circuit 20 during a period corresponding to-the duration of the error signal which is variable depending upon whet her the yarn thickness either exceeds or is less than the standard value. The output of the gating element 19 is in the form of a train of pulses sampled out of the shaped pulses that have been fed thereto from the shaping circuit 17, during the duration of the error signal, said train of sampled pulses being in turn fed to a pulse counting circuit 23 for generating a signal for instigating the cutting of the travelling yarn upon computation of the number of the pulses as will be mentioned later. i

Followed by the gating element 19 is a pulse counting circuit 23 having a preset circuit 24 connected therewith for constantly generating and feeding to said counting circuit 23 a preset signal of a predetermined value. This counting circuit 23 is effective to generate the instigating signal only when the number of the sampled pulses counted thereby coincides or exceeds the predetermined value of the preset signal from the preset circuit 24, said value of said preset signal being selected so as to correspond to a length of the coarse portion tolerable with respect to the measured thickness of the travelling yarn 10. The output signal from said counting circuit 23 which is generated upon coincidence of the sampled pulses with the preset signal is in turn fed to a cutting device 25 through an output stage 26 as a signal for instigating the cutting of the travelling yarn 10, said output stage 26 being preferably in the form of a monostable multivibrator.

However, the counting circuit 23 must be reset to cease its generation of the instigating signal immediately after each instigating signal has been generated so as to get said circuit 23'ready to count the following train of sampled pulses representative of the presence of a different coarse portion of the travelling yarn 10. For this purpose, a reset line 27 is provided which is connected between the discriminator circuit and the counting circuit 23 whereby, upon generation of the error signal from said discriminator circuit 20, the counter circuit 23 can be reset to cease its operation.

The counting circuit23 including the preset circuit 24 herein employed is preferably in the form of a socalled presettable decade counter.

In the arrangement so far described in connection with the foregoing embodiment of the present invention, it is clear that the instigating signal required to operate the cutting device for cutting the travelling yarn 10 can be generated in response to the thickness of said yarn in relation to the length of the coarse portion of the travelling yarn. In other words, even if the thickness of the travelling yarn exceeds, or alternatively decreases below, the standard value, the instigating signal will not be generated unless otherwise the length of the coarse portion of said yarn having such thickness exceeds, or decreases below, the predetermined value. 7

In another preferred embodiment of the present invention shown in FIG. 3, the arrangement is designed such that the thickness of the travelling yarn measured by the thickness measuring unit 16 as exceeding or less than the standard value within a tolerable range can be classified into a plurality of ranks so that the instigating signal for operating the cutting device 25 can be generated only when the length of the coarse portion of the yarn of which the thickness measured belongs to one of said ranks exceeds or is less than one of predetermined values associated with said one of said ranks of thickness, the number of said predetermined values corresponding to the number of said ranks.

For a clear understanding of the embodiment shown in FIG. 3, reference is first made to FIG. 4 in which a program is shown illustrating the various conditions at which cutting of the travelling yarn is carried out. It is to be noted that the program shown in FIG. 4 is in the form of a graph wherein the ordinate is the thickness of the yarn passed through the thickness measuring unit 16 while the abscissa is the length of said yarn measured by the length measuring unit 15.

The conditions shown therein and at which the cutting is, for example, carried out on the travelling yarn are:

I. when the length of a coarse portion of the travelling yarn exceeds the value L if the thickness thereof is measured; as being within a range from the uppermost limit of the standard tolerable range T to the value T,, 2. when the length thereof exceeds the value L, if the thickness thereof is measured as being within a range from the value T, to the value T 3. when the length thereof exceeds over the value I if the thickness is measured as being within a range from the value T to the value T 4. irrespective of the length of the coarse portion of the travelling yarn if the thickness is measured as exceeding the value T and 5. when the length thereof exceeds the value L if the thickness thereof is measured as smaller than the lowermost limit of the tolerable standard range T Thus, it may be said that the uppermost limit of the tolerable standard range of thickness as well as the lowermost limit thereof can be elastically varied in relation to the length of the coarse portion of the travelling yarn. So to speak, even if the measured thickness exceeds or is less than the tolerable standard range, the quality of yarn will not be badly affected unless otherwise the length of the coarse portion is within an appreciable value. 5

The arrangement of the yarn cleaner shown in FIG. 3 has been designed so as to achieve the abovementioned conditions, although the units shown in the graph of FIG. 4 are merely arbitrarily selected to show the various relationships between the thickness and length for the sake of brevity and are not to be considered as indicating any particular unit of measurement.

Referring back to FIG. 3, a plurality of discriminators 20-1, 20-2, 20-3, 20-4 and 20-5 having the individual reference signal generators 22-1, 22-2, 22-3, 22-4 and 22-5 are parallely disposed with their input terminals connected in common with the amplifier 21. The output tertninals of said discriminators, except for that of the discriminator 204 which is directly connected with an OR gating element 28, is connected through AND gating elements 19-1, 19-2, 19-3 and 19-5 with input terminals of counters 23-1, 23-2, 23-3 and 23-5 having the individual preset circuits 24-1, 24-2, 24-3 and 24-5, respectively, the output terminals of which are connected in common with the OR gating element 28. The

OR gating element is in turn connected with the output stage 26 and then to the cutting device 25.

The output terminal of the shaping circuit 17 is connected with the AND gatingelements 19-1, 19-2, 19-3 and 19-5 so that pulses from said circuit 17 can be passed therethrough upon application of the error signal from one or all of the discriminators connected thereto. In a similar manner as in the foregoing embodiment, each of these AND gating elements is adapted tobe triggered by the logical product of the yarn length signal from the shaping circuit 17 and the error. signal fed from the corresponding one of the discriminators thereby to feed a pulse train to one of the counters associated with said corresponding discriminator.

The discriminators 20-1 to 20-5 are adapted to receive reference signals of different values from the reference signal generator 22-1 to 22-5. The lowest value is given to the discriminator 20-5, the second lowest value to the discriminator 20-1, the third lowest value to the discriminator 20-2, the fourth lowest value to the discriminator 20-3, and the highest value to the discriminator 20-5. Similarly, the counters 23-1 to 23-5 are adapted to receive preset signals of different values from the preset circuits 24-1 to 24-5. The lowest value is given to the counter 23-3, the second lowest value to the counter 23-2, the third lowest value to the counter 23-1, and the highest value to the counter 23-5.

Accordingly, if the value of the signal representative of the yarn thickness which has been fed from the thickness measuring unit 16 is assumed to be within a range of from the value of the reference signal applied to the discriminator 20-3 to the value of the reference signal applied to the discriminator 20-2, both discriminators 20-2 and 20-1 can generate error signals. On the other hand, since the signal representative of the yarn length is constantly supplied through the shaping circuit 17 to the AND gating elements 19-1 to 19-5, upon receipt of the error signals from the discriminators 20-1 and 20-2 only to gating elements 19-1 and 19-2 can be triggered on thereby to feed respective pulse trains to the associated counters 23-1 and 23-2. The pulse trains thus fed to the counters 23-1 and 23-2, respectively, can be counted by the corresponding counters. However, since the value of the preset signal fed to the counter 23-1 is smaller than that fed to the counter 23-2 as hereinbefore described, the counter 23-l completes its counting operation earlier than the other counter 23-2 and, hence, upon coincidence of themeset signal with the value of the pulse train counted by the counter 23-1, the latter can generate the instigating signal for operating thecutting device 25. This instigating signal is, of course, fed from the counter 23-1 through the OR gating element 28, then the output stage 26 and finally to the cutting device 25.

For resetting the counters for the same purpose as in the foregoing embodiment, the discriminator 20-1 to which the smallest reference signal is applied relative to the yarn thickness within the tolerable standard range is connected with the counters 23-1 to 23-5 by means of respective reset lines 27-1, 27-2 and 27-3.

In the event that the value of the yarn thickness signal fed from the thickness measuring unit 16 is smaller than the tolerable standard range, the output signal of the discriminator 20-5 is adapted to be inverted by an inverter 29 provided between said discriminator 20-5 and the AND gating element 19-5. The associated gating element 19-5 can be triggered on by the logical product of said inverted signal and the signal representative of the yarn length and, thereafter, the output signal from the gating element 19-5 is treated in substantially the same way as hereinbefore described. However, in view of the fact that the travelling yarn has a sufficient thickness greater than the thickness predetermined by the discriminator 20-5, the latter continuously generates the error signal. Accordingly, only tolerable standard range, no error signal can be generated from the discriminator 20-5. Therefore, the output signal of the discriminator 20-5 that has been inverted by the invertor 29 represents the yarn of the thickness smaller than the tolerable standard range.

The reference signal to be applied to each of the discriminators 20-1 to 20-5 from the respective generators 22-1 to 22-5 is in the form of voltage and, therefore, the value of said reference signal can be easily adjusted. In addition, the value of the preset signal to be applied from the preset circuit 24-1 to 24-5 to the counter 23-1 to 23-5 can also be adjusted.

In the foregoing embodiment shown in FIG. 3, each counter 23-1 to 23-5 is a presettable decade counter. However, instead of the presettable decade counter, an adder may be employed for the same purpose, as shown in FIG. 5. In this case, each of the adders 23'-l, 23'-2, 23-3 and 23-5 is effective to generate an output signal each time the pulse train is applied thereto from the corresponding AND gating element, said output signal from said adder corresponding with the sum of voltages of the pulse signals thus applied from the AND gating element. This output signal from any one of the adders is adapted to be fed to an additional discriminator 30 through a proportional adder generally indicated by 31.

In this arrangement, if the value of the signal representative of the yarn thickness which has been fed from the thickness measuring unit 16 is assumed to be within a range from the value of the reference signal applied to the discriminator 20-3 and the value of the reference signal applied to the discriminator 20-2, both discriminators 20-2 and 20-1 can generatethe error signals. In the same way as in the foregoing embodiment, the two gating elements 19-1 and 19-2 can be triggered on thereby to feed respective pulse trains to the associated adders 23'-l and 23'-2,' which are in turn counted by said adders 23-l and 23-2. Each output signal from said adders 23'-1 and 23-2 is then fed to the proportional adder 31. However, since this adder 31 is provided with resistors 31a, 31b, 31c, and 31d, and resistor 31c with amplifier 31f, of properly selected different values, the output signals thus fed thereto can be multiplied respectively by a suitable coefficient.

The instigating signal for operating the cutting device 25 can be generated only when the level of the output signal from the proportional adder 31 coincides with the preset value of the additional discriminator 30.

However, it is to be noted that, by suitably changing the value of each of the coefficients, it can be appreciated that the arrangement shown can achieve conditions different from that shown in FIG. 4.

In the embodiments shown in FIGS. 2 and 3, the discriminator 20-4 is adapted to correspond with the highest rank of thickness. Accordingly, if the measured thickness of the yarn 10 exceeds the value of the reference signal applied to the discriminator 20-4, the signal representative of the measured thickness can be directly applied to the OR gating element 28 so that the cutting of the travelling yarn 10 can be performed irrespective of the length of the coarse portion of the yarn. However, in practice, in view of the fact that some inconvenience will occur if the instigating signal is directly supplied to the cutting device 25 through the discriminator 20-4 while transference of the yarn from the slubbing bobbin 11 to the cone I2 is stopped or interrupted, the employment of an AND gating element is recommended. In this case, input terminals of the additional AND gating element are respectively connected with the discriminator 2 -4-and the shaping circuit 17 while the output terminal thereof is connected with the OR gating element 28.

In the event that two or more coase portions of yarn which are closely located as shown in FIG. 1 are passed through the thickness measuring unit 16, it is preferable to remove both coarse portions. To achieve this, a further preferred embodiment is provided such as shown in FIG. 6 which is a modification of FIG. 2. The

only difference between the two embodiments shown in FIG. 2 and FIG. 6 is that in FIG. 6 there is provided a reset counter 32 having a preset circuit 33 capable of constantly generating a preset signal of a fixed value and supplying it to said reset counter 32, said reset counter 32 being disposed in such a way that an input terminal thereof is connected with the shaping circuit 17, another input terminal thereof is connected with the discriminator and an output terminal thereof is connected with the counter 23 for resetting the latter by means of an output signal from said reset counter 32.

In this arrangement, so long as the measured thickness of the travelling yarn 10 is within the tolerable standard range, the counter 32 merely acts to count the number of pulses applied thereto from the shaping circuit 17. However, if the measured thickness thereof is over the uppermost limit of the tolerable standard range, but less than the value of the reference signal applied from the reference signal generator to the discriminator 20, the latter can generate an error signal both to the AND gating element 19 and to the reset counter. At this time, the reset counter 32 can be reset to cease its counting operation while the counter 23 commences to count the number of pulses included in an output signal from the gating element 19 which is representative of the logical product of the signals both from the shaping circuit 17 and from the discriminator 20. If the counted number of'the pulses is smaller than the value of the preset signal fed to the counter 23, this counted number of pulses can be stored in such counter 23 without the instigating signal being generated therefrom. However, if the counted number of pulses is equal to or greater than the value of said preset signal, the counter 23 commences to re-count the number of the pulses and, upon coincidence of the recounted number of the pulses with the value of the preset signal fed to the counter 23, the instigating signal can be generated and supplied to the cutting device 25. However, it is to be noted that, if the length of the yarn from one course portion to another is such that the value of a signal representative of such length which is counted by the preset counter 32 is smaller than the value of a preset signal fed from the preset circuit 33 to the counter 32, the reset signal will not be generated and supplied from the counter 32 to the counter 23. Only when the number of pulses counted by the counter 32 coincides with the value of the preset signal applied thereto, the reset signal can be generated and supplied to the counter 23 to stop the counting operation of the latter even though the pulses representative of the first measured coarse portion are stored in the counter 23.

Thus, it is clear that the arrangement shown in FIG.

6 is effective to generate the instigating signal for operating the cutting device 25 even when the closely located coarse portions of the travelling yarn, of which the values of signals representative of respective thickness of such coarse portion are each lower than the value of the preset signal applied to the counter 23, have been passed through the thickness measuring unit 16 unless otherwise the sum of said values of said signals is equal or higher than the value of said preset signal. In practice,-the arrangement shown in FIG. 6 is made in a way such as illustrated in FIG. 7.

In the logical circuit of FIG. 7, for the reason as hereinbefore described, the AND gating element 19-4 is provided with its two input terminals connected with the discriminator 20-4 and the shaping circuit 17, respectively, and the output terminal with the OR gating element 28'. The counter 32a is adapted to be reset by a signal which has been inverted by an inverter 29b to which an error signal from the discriminator 20-1 is adapted to be applied, while the counter 32b is adapted to be reset by the error signal from the discriminator 20-5 without being inverted. I

It is to be noted the embodiments shown in FIGS. 1 and 6 can be modified such as shown in FIGS. 8 and 9, respectively. In the arrangements of FIGS. 8 and 9, the discriminator 20 that has been disposed between the amplifier 21 and the AND gating element 19 in FIG. I is disposed between the element 19 and the counter 23. However, the modification of FIG. 8 requires an inverter 34 and a NAND gating element 35 while that of FIG. 9 requires aninverter36.

Although the presentinvention has been fully describedin conjunction with the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications are apparent to those skilled in the art. For example, although the present invention has been described as having the yarn length measuring unit 15 located at an intermediate portion between the slubbing bobbin 11 and the crosswound cone 12, for obtaining the signal representative I of the yarn length, detection of the yarn length may be carried out at the following positions or bymeans of the following methods with reference to FIG. 10.

A Detecting the movement of the travelling yarn 10 above the slubbing bobbin 11 by means of a plurality of photosensitive elements 40, as indicated at A,

B Detecting the passage of yarn having equally spaced markings such as made by water, ions or paint, by a detector 41 as indicated at B,

C Detecting the rotation of a disc 42 coaxially connected with the roller 15c having no holes 15d, by

means of an electromagnetic device 43, as shown at C, D Detecting the lateral movement of the travelling yarn 10 which is brought about by the split guiding drum 13 by photosensitive elements 44, as shown at D, E Detecting the rotation of the drum 13, by a disc 45 and magnetic device 46, as indicated at E,

F Detecting the frequency of a motor M for driving the drum 13, as indicated at F,

G Detecting the rotation of the drum 13 by means of a roller 47 coaxially connected therewith, a disc 48 connected to the roller, and a magnetic device 49, as

indicated at G,

H Detecting the rotation of the spindle of the cross-wound cone 12 by detecting the rotation of a disc 50 connected thereto by a magnetic device 51, as indicated at H,

l Detecting the peripheral velocity of the rotating cross-wound cone 12 by means of a roller 52 rotatable in contact with the peripheral surface of said cone 12, a disc 53 connected to the roller 52, and a magnetic device 54, as indicated at l, and so on.

For obtaining the signal representative of the yarn thickness, other than as hereinbefore described, a feeler member 55 may be employed as indicated by J.

What is claimed is:

1. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal representative of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for generating an error signal of a certain duration when the value of said thickness signal departs from a predetermined value, means for permitting the passage therethrough of a train of pulses which is the logical product of said error signal and said length signal, means for counting the number of the pulses of said train and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, and means for cutting the travelling yarn upon receipt of said instigating signal.

2. The apparatus as claimed in claim 1, wherein said first measuring means comprises a grooved roller having a plurality of equally spaced holes in parallel relation to the axis of said roller, a source of light and a photosensitive element disposed on the path of light transmitted from said light source, said grooved roller being disposed such that said path of light can be intercepted or established in response to the absence or presence of any one of said holes in said path as said roller is rotated in contact with the. travelling yarn, whereby the signal representative of the yarn length can be obtained.

3. The apparatus as claimed in claim 1, wherein said counting means comprises at least one presettable decade counter.

4. The apparatus as claimed in claim 1, wherein said counting means comprises at least one adder.

5. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal representative of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for generating an error signal of a certain duration when the value of said thickness signal departs from a predetermined value, means for permitting the passage therethrough of a train of pulses which is the logical product of said error signal and said length signal, means for counting the number of the pulses of said train and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, means for resetting the counting means to cease its counting operation upon generation of another electrical signal representative of the subsequently measured thickness of the travelling yarn and means for cutting the travelling yarn upon receipt of said instigating signal.

6. The apparatus as claimed in claim 5, wherein said resetting means comprises at least one reset counter.

7. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal'representativc of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for permitting the passage therethrough of a train of pulses which is the logical product of said thickness signal and said length signal, means for generating an error signal of pulses'when the value of said signal representative of said .logical product departs from a predetermined value, means for counting the number of the pulses of said error signal and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, means for resetting the counting means to cease its counting operation upon generation of another electrical signal representative of the subsequently measured thickness of the travelling yarn and means for cutting the travelling yarn upon receipt of said instigating signal.

il 1.! i I t 

1. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal representative of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for generating an error signal of a certain duration when the value of said thickness signal departs from a predetermined value, means for permitting the passage therethrough of a train of pulses which is the logical product of said error signal and said length signal, means for counting the number of the pulses of said train and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, and means for cutting the travelling yarn upon receipt of said instigating signal.
 2. The apparatus as claimed in claim 1, wherein said first measuring means comprises a grooved roller having a plurality of equally spaced holes in parallel re-lation to the axis of said roller, a source of light and a photosensitive element disposed on the path of light transmitted from said light source, said grooved roller being disposed such that said path of light can be intercepted or established in response to the absence or presence of any one of said holes in said path as said roller is rotated in contact with the travelling yarn, whereby the signal representative of the yarn length can be obtained.
 3. The apparatus as claimed in claim 1, wherein said counting means comprises at least one presettable decade counter.
 4. The apparatus as claimed in claim 1, wherein said counting means comprises at least one adder.
 5. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal representative of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for generating an error signal of a certain duration when the value of said thickness signal departs from a predetermined value, means for permitting the passage therethrough of a train of pulses which is the logical product of said error signal and said length signal, means for counting the number of the pulses of said train and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, means for resetting the counting means to cease its counting operation upon generation of another electrical signal representative of the subsequently measured thickness of the travelling yarn and means for cutting the travelling yarn upon receipt of said instigating signal.
 6. The apparaTus as claimed in claim 5, wherein said resetting means comprises at least one reset counter.
 7. An apparatus for removing coarse yarn from a travelling yarn which comprises a first measuring means for measuring the thickness of said travelling yarn and generating an electrical signal representative of the measured thickness, a second measuring means for measuring the length of said travelling yarn and generating an electrical signal representative of the measured length, means for permitting the passage therethrough of a train of pulses which is the logical product of said thickness signal and said length signal, means for generating an error signal of pulses when the value of said signal representative of said logical product departs from a predetermined value, means for counting the number of the pulses of said error signal and generating an electrical signal for instigating the cutting of the travelling yarn only when the value of said pulses counted departs from a predetermined value, means for resetting the counting means to cease its counting operation upon generation of another electrical signal representative of the subsequently measured thickness of the travelling yarn and means for cutting the travelling yarn upon receipt of said instigating signal. 